Carburetor



Aug. 25, W36 M. E. CHANDLER 2,051,820

CARBURETOR Filed Feb. 25, 1934 :s Sheets-Sheet 1 W 69 I 62 mo mlmlxlma l\ IN V EN TOR.

M/hon E. Chandler Aug, 25, 1936., M. E. CHANDLER CARBURETOR Filed Feb. 25, 1934 3 Sheets-SheebZ Patented Aug. 25, I 1936 Milton E. it dler,

to Bendix Aviation @orporation, South Bend, Ind, a corporation of Delaware onth Bend, ind, assignor Application February 23, 19%, Serial No. 312,492

This invention relates to carburetors and more particularly to carburetors of the fuel lift type, which draw fuel from a supply tank positioned at a lower level than the fuel nozzle of the carburetor. r

An object of this invention is to provide an improved carbureting device which will lift fuel from the supply tank to a chamber positioned above the fuel nozzle of the carburetor, and supply the carburetor with fuel -at constant pressure.

A further object is to provide an improved carbureting unit of simplified construction which will eliminate the fuel pump or vacuum tank ordinarily used therewith.

A still further object is to provide an improved fuel lift carburetor of simplified construction, which may be economically manufactured and will be economical and positive in operation.

Other objects and advantages of the invention will be apparent from the following detailed description, and from the illustrative embodiments of the invention in the accompanying drawings, which are submitted merely for purposes of illustration, and are not intended to 'define the scope of the invention, reference being had for that purpose to the appended claims.

In the drawings wherein similar reference characters refer to similar parts throughout the several views:

Figure 1 is a vertical section illustrating a preferred embodiment of the invention;

Figure 2 is a sectional view taken on line 2-2 of Figure 1;

Figure 3 is an enlarged sectional view showing a modified form of valve;

' Figure 4 is a plan view illustrating a modified form of the invention;

Figure 5 is a vertical section taken on line 5-5 of Figure 4;

Figure 6 is a vertical section taken on line 8-6 of Figure 4; and K Figure '7 is a diagrammatic view showing the fuel passages disclosed in Figures 4, 5, and 8.

Referring more particularly to Figures 1 and 2, there is shown a carbureting unit having an which supplies fuel to a plurality of engine cylinders.

The flow of air through airhorn I8 is controlled by a choke valve l8 mounted on a shaft 58 and provided with a spring pressed poppet 6 valve 80 to permit a small amount of air to pass through airhorn it when the suction is great enough to compress spring 22.

1 Fuel is supplied to the carburetor from float chamber 24, through a pair of fuel ducts 26 each of which terminates in a fuel discharge nozzle 28 positioned to discharge at the most restricted portion of a primary venturi 88 which in turn discharges at the most restricted portion of a secondary venturi 32. The venturis 38 and 32 are carried in middle body section l2 and are preferably formed integral therewith. The lower end of secondary venturi 32 is a slip lit in the upper portion of barrel 34 formed in the throttle body section l4. The flow of mixture through each of the carbureting passages thus formed by the three described sections is controlled by a throttle valve 36 mounted on a shaft 38 journalled in the walls of the throttle body section I4. I

A flange 48 formed integral with the airhorn section It) provides a cover for float chamber 24 and accommodates a needle valve 42 which when actuated by lever 44,.flxed to float 48 and pivoted at 48, controls the flow of fuel into said float chamber and maintains a constant level therein. The upper portion of flange 40 has a recess which cooperates with a corresponding recess in the lower portion of a superposed tank section 58 to form a fuel reservoir 52 which receives fuel from chamber 54 through an outlet member 56 which terminates in a cup-shaped member I08 and is controlled by a gravity-actuated disk valve I88.

Chamber 54 accommodates a float 58 which is pivotally mounted on a pin 18 positioned in the lowerends of two downwardly extending studs 58. An arm 84 fixed to float 58 connects by means of a spring 88 with a lever 88 mounted on pin 18. A float actuated slide valve 68 operates to selectlvely subject'chamber 54 to atmospheric pressure or a partial vacuum derived from two auxiliary venturis, as described below. Lever 60 connects with slide valve 68 in such a manner as to move the valve from one of its extreme positions to the other when the spring 66 is moved past the dead center, formed by pin 18, by movement of float 88. As float 58 rises, arm 64 rotates in the clockwise direction moving spring 88 past pin 18 and causing lever 80 to exert a lateral pull on slide valve 66 which will move the valve to the left, thereby opening passage 30 to allow air to enter chamber 56 from duct 12 which communicates with the usual air cleaner (not shown) attached to airhorn ill. The pressure existing in the upper portion of chamber 56 will immediately rise to atmospheric, and fuel will flow out of said chamber through outlet member 56. As the fuel level in chamber 5 drops, float 58 will rotate in a counterclockwise direction around pin 16, thereby carrying arm 66 to the right. As spring 66 passes the dead center at "i6, it will cause lever 60 to exert an increasing lateral pull on slide valve 66 in the opposite direction as the fuel level drops, and will finally overcome the resistance of said valve and move it to the right, closing air inlet passage 10 and opening port 16 and duct 16 leading to auxiliary venturis 80 and 82, which will exert suction in chamber 56 and draw fuel from supply tank 66 to chamber 56 through duct 86 while at the same time holding valve 606 to its seat to prevent flow of fuel from chamber 56 to reservoir 52. A check valve 98 is positioned in fuel duct 86 to prevent fuel from flowing from chamber 50 back to the tank 84.

The auxiliary venturis 86 and 62 are positioned in series in the walls of the main carbureting passage 88. The primary venturi 80 is carried in the middle body section I 2 and discharges at the most restricted portion of the secondary venturi 62 carried in the throttle body section I4 which communicates with both barrels 34 through a passage 90, the outer end of which is closed by a plug 92. Annular passage 90 communicates wth barrels 34 through outlet ports 9| anterior to throttle valve 36. A two-leaf spring-pressed valve 94 is mounted on a shaft 96 in each barrel 34 for the purpose of insuring a predetermined minimum suction at ports 9|, so that suflicient air will be forced to flow through the auxiliary venturis, even at wide open throttle, to lift fuel from storage tank 84 to chamber 54.

Auxiliary passages I lead from an annular chamber at the throat of venturi 80 and discharge into the barrels 34 posterior to throttle valves 36 to provide suction to create a partial vacuum in chamber 54 when the engine is idling with throttles 36 fully closed. Fuel for idling purposes is supplied through the conventional idling passages I02 and I04.

Figure 3 illustrates a type of valve which may be used instead of cylindrical slide valve 68 described above. n comprises a double-ended needle valve 69 slidable endwise to subject chamber 54 to suction or atmospheric pressure depending upon the position of float 58.

The operation of the device thus far described is as follows. It is apparent from the foregoing description that irrespective of the position of throttle valves 36 sufficient suction will at all times be present in the throat of primary venturi 80 to lift fuel from supply tank 04 to. upper chamber 54. When the fuel level in chamber 54 is at its highest point, represented by the line Y-Y in Figure 1, slide valve 68 will be in the position shown in Figure 1, in which position it permits air to enter through duct 12 and passage 10 to maintain the pressure in chamber 54 at atmospheric. The resulting head of fuel unseats valve I06, permitting the fuel in chamber 54 to be discharged into reservoir 52 and thence into float chamber 24 at a rate controlled by needle valve 42. As the fuel level in chamber 54 lowers, float 58 moves spring 66 past the dead center position represented by pin 16, whereupon lever 60 aoaaeao will move valve 66 to the right, thereby closing atmospheric duct Z2 and opening port 56 to permit the suction developed at venturi 60 to be transmitted to the chamber 56. The suction draws valve 906 tightly to its seat, and draws fuel from the supply tank 86 to chamber 56, thus gradually raising the fuel level therein. Float 58 is moved upwardly by the rising fuel level, and when it approaches the position shown in Figure l, the spring 66 will be moved to the left past dead center 16, and will thus overcome the resistance of valve 66 and move it to the left, thereby closing port it and duct '36 leading to the auxiliary venturis and opening duct 12 to restore the pressure in chamber 56 to atmospheric. The weight of the fuel will thereupon force valve I06 from its seat and the fuel will flow to reservoir 52, as before described, and the cycle will then be repeated.

Figures 4, 5, 6, and 7 illustrate a carburetor similar in many respects to the preferred embodiment disclosed inFigures 1 and 2, but comprising only one barrel. It includes an upper or airhorn section H0, 2. middle body section- H2 and a throttle body section H4.

The flow of air through airhorn III] is controlled by a choke valve H6 mounted on a shaft H6 and provided with a spring-pressed poppet valve I20 to permit a small amount of air to pass through airhorn IIO when the suction therein is sufficient to compress spring I22.

Fuel is supplied to the carburetor from float chamber I24, through fuel duct I26 which terminates in a fuel discharge nozzle I28 positionedto discharge at the most restricted section of a primary venturi I30 which in turn discharges at the most restricted section of a secondary venturi I32, the lower end of which is carried in the upper portion of barrel I34 formed in throttle body section H4.

The flow of combustible mixture through carbureting passage II thus formed by the three described sections is controlled by a throttle valve.

I36, mounted on a shaft I38 journalled in the walls of throttle body section I I4.

A flange I40 formed integral with airhorn section IIO provides a cover for float chamber I24 and provides an intermediate fuel compartment I60. An upper chamber I42 positioned above and secured to flange I40 accommodates a float I44 which actuates'a slide valve mechanism comprising a" cylindrical valve member I46 and two levers I48 and I50 mounted on pin I52. The free end of lever I48 is attached to cylindrical valve I46 while the free end of lever I50 is attached to link I54 fixed to float I44. A tension spring I56 fixed to ears I6I formed on levers I48 and I 50 tends to move said levers away from a position of alinement with each other.

Flange I40 has a downwardly extending portion forming an intermediate fuel compartment I60.- The upper and intermediate fuel compartments are connected by means of a gravity actuated check valve I62 in such manner that fuel may flow by gravity from upper chamber I42 to intermediate chamber I60 from which point fuel is admitted to float chamber I24 by means of fuel duct I66 and the rate of flow is regulated by a needle valve I68 actuated by float I in the conventional manner.

Suction to lift fuel from supply tank I12 to upper chamber I42 is derived from two venturis I16 and I18 set at right angles to each other. Suction duct I14 leading from upper chamber I42 communicates with the most restricted section of primary venturi I16, which discharges at aosmao the most restricted section of secondary venturi 818, which in turn discharges into a hollow flange ll communicating with the main carbureting passage H anterior to throttle valve 536 and posterior to spring pressed valve ltd.

Sufficient suction is therefore always present in primary venturi we to draw a proper quantity of air through the auxiliary venturis to produce adequate suction to lift fuel from supply tank M2 to upper chamber M2, from which point fuel is directed through the remaining chambers of the carburetor 'by force of gravity.

The operation of this device is as follows. When the engine is running, suction is applied to duct lid and transmitted to chamber M2 by the valve mechanism described above. The difierential pressure will draw fuel from supply tank W2 through duct i82 to chamber m2 and as the fuel level therein rises, float M l will be lifted. Link i5 3 fixed to float lil will thereupon lift lever I50, extending spring H55. When lever I50 rises above the dead center position spring 855 will force lever M8 upward, thereby moving slide valve was upward, closing suction duct lid, opening vent its, and subjecting chamber 32 to atmospheric pressure. The weight of the entrained fuel will immediately force valve member let from its seat and the fuel will flow by force of gravity into chamber E50. When the fuel level in chamber i432 drops to a point such that levers I58 and I50 move downward past dead center position, spring lat will force lever Mil downward, thereby moving slide valve M5 downward, opening suction duct lit and closing vent we so that suction will again be exerted in chamber M2 which will hold valve member let on its seat and draw fuel from tank H2 through duct we to said chamber.

The flow of fuel from compartment I80 is regulated by float actuated needle valve I68 so that substantially constant fuel level will be maintained in float chamber I26 at all times.

An acceleration pump similar to that disclosed in the copending application of Hunt et al., Serial No. 701,740, filed December 11, 1933, is incorporated with this carburetor and comprises chiefly, an acceleration pump cylinder I90 formed integral with the middle body section H2, 9. mston I92 slidable therein and a piston actuating mechanism consisting of a piston rod I04 and an arm I98 pivotally connected therewith and actuated upon movement of the throttle valve I" by means of a connecting linkage not shown. An economizer valve I98 is positioned in the lower portion of cylinder I90 and comprises a springpressed valve member 200 having a stem 202 projecting above the surface of said valve and designed to be engaged by the end of piston I92 to hold said valve open and permit a steady discharge of fuel through-duct 204 when the engine is operating at substantially. full throttle position. A check valve 206 positioned between the economizer valve I98 and float chamber I20 operates to prevent fuel from flowing back into the float chamber when the acceleration pump is actuated.

I claim:

1. A carbureting device having a main carbureting passage with a throttle'valve and an auxiliary spring pressed-valve mounted therein, a plurality of chambers at different levels, floats in the upper and lower chambers, a, float actuated valve in the upper chamber, fuel inlet means into said upper chamber, a check valve to permit the flow of fuel in only one direction in said inlet means, a gravity seating valve between said upper chamber and a middle chamber, a float actuated valve between said middle chamber and lower chamber, suction means comprising a primary and secondary venturi mounted in series in said main carbureting passage, said secondary venturi communicating with said main carbureting passage between said auxiliary valve and said throttle valve, and suction transmitting means between said upper chamber and the throat of said primary venturi controlled by said float actu ated valve.

2. A carbureting device having a main carbureting passage with choke and throttle valves and an auxiliary spring-pressed valve mounted therein, a plurality of chambers at different-levels, floats in the upper and lower chambers, a float actuated valve in the upper chamber, fuel inlet means into said upper chamber, a check valve to permit the flow of fuel in one direction only in'said inlet means, a middle chamber, a

pressure responsive valve between said upper 7 venturi to said main carbureting passage communicating therewith at a point between said auxiliary spring pressed valve and said throttle valve, and suction transmitting means between said upper chamber and the throat of said primary venturi.

3. In a fuel lift carburetor having a main carbureting' passage with a throttle valve and an auxiliary valve mounted therein, a plurality of chambers at different levels, fuel inlet means provided with a check valve to permit fuel to flow only into the upper chamber, controlling means for regulating the flow of fuel from said upper chamber to the lower chambers, floats in the upper and lower chambers, float controlled means for maintaining constant fuel level in the lowest chamber, suction means comprising two auxiliary venturis communicating with the main carbureting passage and discharging into said main carbureting passage between said auxiliary valve and said throttle valve, suction-transmitting means connecting said auxiliary venturis and said upper chamber, a vent in said upper chamber, a float actuated slide valve in said upper chamber, and means to actuate said valve producing successively a partial vacuum and atmospheric pressure in said upper chamber.

4. In a fuel lift carburetor, an induction passage, a fuel jet and throttle valve therein, a pressure responsive valve in said passage between the fuel jet and throttle valve, a venturi connected in parallel with the passage and having its inlet communicating with the passage anterior to the pressure responsive valve and its outlet communicating with the passage between the pressure responsive valve and the throttle, and suction operated fuel lifting means communicating with said venturi, comprising a fuel reservoir supplying fuel to said fuel jet and subjected above the fuel level therein to the suction developed at said venturi.

5. A carburetor comprising a carbureting passage, a fuel jet therein, a throttle valve posterior to the fuel jet and controlling the carbureting 4 acaaeac sage having an air inlet of constant-efiective cross-section at normal operating temperatures, a fuel inlet to said carbureting passage, a fuel supply system leading to said fuel inlet, a throttle valve posterior to the fuel inlet and controlling the carbureting passage, a pressure-responsive valve in the carbureting passage posterior to the fuel inlet and anterior to the throttle valve, and means for actuating said fuel supply system comprising a suction-multiplying member connected to a part of said system and communicating with the carbureting passage posterior to the pressure-responsive valve and anterior to'the' throttle valve.

7. A carburetor comprising a carbureting 'p'assage having an air inlet, a choke valve controlling said air inlet and designed to be fully opened at normal operating temperatures, a fuel inlet to said carbureting passage, suction operated fuel lifting means supplying fuel to said fuel-inlet, a throttle valve posterior to said fuel inlet and controlling the carbureting passage, variable flowrestricting means in the carbureting passage between the fuel inlet and the throttle valve, and-- means for energizing said fuel lifting means coinprising a suction-multiplying member communicating with the carbureting passage posteriorto the flow-restricting means and anterior to'the throttle valve. r

8. In a fuel supply system for an internal combustion engine, a carburetor having an induction passage, a venturi in said passage, a fuel nozzle discharging within said venturi, a throttle valve and a suction responsive valve positioned in seties in said induction passage posterior to said,

nozzle, a fuel reservoir, and means for supplying fuel to said reservoir comprising a venturi connected thereto and communicating with the in-. duction passage between said valves.

9. In a fuel supply system for an internal com-' bustion engine, a carburetor having an induction passage, a venturi in said passage, a fuel nozzle discharging within said venturi, a throttle valve and. asuction-responsive valve positioned in series in said induction passage posterior to said fuel nozzle, and means for supplying fuel to said nozzle comprising a fuel reservoir and a venturi connected thereto and having its inlet communicating with the induction passage anterior to saidvalves and its outlet communicating with the induction passage between said valves.

- 10. In afuel supply system for an internal combustion engine, a carburetor having an induction passage, aventuri in said induction passage, a fuel noz'zle' discharging within said venturi, a

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suction responsive valve and a throttle valve positioned in series in said induction passage posterior to said nozzle, a choke valve adjacent the.

inlet of said induction passage and designed to leave the inlet unobstructed at normal operating temperatures, and means for supplying fuel to said "nozzle comprising a fuel reservoir and a suction-multiplying venturi having its inlet communicating with the induction passage anterior to both said valves, its outlet communicating.

with the induction passage between said valves, and its throat communicating with said fuel rese'rvoir to transmit suction thereto.

MILTON E. CHANDLER. 

